According to conventional power supply circuits and high voltage/heavy current circuits such as power conversion circuits, a cement resistor, which is fabricated by putting a winding type resistor unit or a metal oxide film resistor unit into a ceramic case and then sealing it with silicon resin (cement), or an enamel resistor fabricated by winding a resistance wire around a porcelain bobbin and covering it with enamel, etc. are used. In particular, since the power converter for vehicles such as hybrid electric vehicles (HEV) needs a high power resistor for discharging the electric charge accumulated in the smoothing capacitor, a large-sized cement resistor is used.
Moreover, the power resistor designed to be mountable on a printed circuit board in a state being attached to a heat sink has been developed (e.g., Patent Document 1). According to the resistor given in Patent Document 1, parts of metal terminals (lead wires) 21 and 22 projecting from the bottom of a long and narrow synthetic resin main body 10 are embedded in a resin main body, a portion exposed outside of the resin main body extends linearly and has a shape in which width in the vicinity of the tip part is smaller than that on the main body side, so as to be mountable on a printed circuit board.
On the other hand, Patent Document 2 discloses a structure of a fixed resistor for heating and freeze proofing from which coated electric wires are taken out, wherein a circuit formed surface on a ceramic substrate is covered by an insulating material, and the covered wires are taken out from the insulating coating part.